Sofa bed



FIG. 1 is a front perspective view of a sofa bed showing my new design;

FIG. 2 is a right side elevational view, the left side being a mirror image thereof;

FIG. 3 is a top plan view;

FIG. 4 is a front elevational view;

FIG. 5 is a rear elevational view;

FIG. 6 is a bottom plan view thereof; and,

FIG. 7 is a front perspective view of a sofa bed showing my new design in opened condition. 

The ornamental design for a sofa bed, as shown and described. 